At present, the Next Generation Network (NGN) is a hot research topic in the field of the current communication standards, it uses the Internet Protocol (IP) packet technology as its bearer network technology, integrates fixed communication and mobile communication, and can provide richer multimedia services, such as, emerging services with a real-time requirement (IP TV, video conference, multimedia remote teaching, video on demand, and the like). These services require a communication network to provide support for efficient end-to-end Quality of Service (QoS). Moreover, since users have increasing high requirements for the service quality of the network, providing the end-to-end QoS is one of the core problems of the NGN.
The International Telecommunication Union-Telecommunications standardization sector (ITU-T) is a telecommunication sector of the International Telecommunication Union (ITU), which has established standards related to the resource and admission control. In the latest draft of Resource and Admission Control Functions (RACF) published by the ITU-T, the functional structure of the RACF is provided. As shown in FIG. 1, the RACF is composed of two portions which are respectively a Policy Decision Functional Entity (PD-FE) and a Transport Resource Control Functional Entity (TRC-FE), wherein the TRC-FE interacts with a transmission function via an Rc, and interacts with a Transport Resource Enforcement Functional Entity (TRE-FE) via an Rn; and the PD-FE interacts with the TRC-FE via an Rt, interacts with a Customer Premises Network (CPN) via an Rh, interacts with a Policy Enforcement Functional Entity (PE-FE) via an Rw, interacts with Service Control Functions (SCF) of a service layer via an Rs, interacts with Network Attachment Control Functions (NACF) via an Ru, and the PD-FE interacts with other next generation networks via an Ri interface.
Besides, the PD-FE is relevant neither to transmission techniques nor to the SCF. The PD-FE makes a final decision for resource and admission control based on network policy rules, service information provided by the SCF, transport layer subscription information provided by the NACF, and resource availability decision result provided by the TRC-FE.
The TRC-FE is irrelevant to services but relevant to the transmission techniques. The TRC-FE is responsible for collecting and maintaining transmission network information and resource state information. Upon receiving a resource request from the PD-FE, the TRC-FE performs a resource-based admission control based on the QoS, the priority demand, the information of resource availability and the transmission-related policy rules.
A transport layer is composed of a Policy Enforcement Functional Entity (PE-FE) and a Transport Resource Enforcement Functional Entity (TRE-FE). The PE-FE executes the policy rules delivered by the PD-FE. The PE-FE is a packet-to-packet gateway and can be located between the Customer Premises Network (CPN) and an access network, between the access network and a core network, or between the networks of different operators, and is a key node which supports the traversing of a Network Address Translator (NAT), a port address translation control, and a dynamic QoS control. The TRE-FE executes the transmission resource policy rules delivered by the TRC-FE, of which the range and functions as well as the Rn interface need to be further researched and are not within the research scope of the R2 phase.
Currently, in order to settle the resource and admission control relating to inter-domain interaction and supporting roaming, relevant research institutes provide a configuration diagram of an RACF network as shown in FIG. 2. In FIG. 2, the SCF is located in an NGN visited network and interacts with the PD-FE of the NGN visited network; the PD-PE of the visited network interacts with the PD-FE of an NGN home network via the Ri interface; and the PD-FE interacts with the PE-FE and TRC-FE of the current network via the Rw and Rt interfaces, respectively. In the scene of FIG. 2, the NACF of the NGN visited network can only obtain user default access information rather than user QoS subscription information of the NACF of the home network.
With respect to the case above, a technical solution for resource and admission control relating to inter-domain interaction and supporting roaming has not been proposed in the prior art.
In the prior art, the SCF is generally located in the NGN home network and interacts with the PD-FE of the NGN home network, as shown in FIG. 3. FIG. 4 is a chart showing the resource requesting flow based on the case as shown in FIG. 3 in the related art, the flow includes the following steps:
401: a user initiates a service request and sends a request message to an SCF to trigger the SCF to generate a resource initialization request;
402: the SCF determines QoS requirement parameters (e.g. bandwidth, service type, etc.) of the requested service, and then sends, to a PD-FE of a home network (denoted by PD-FE(H)), a resource initialization request message (reservation) carrying a media stream description, QoS parameters, and the like, to request an RACF to perform authorization and reservation of QoS resource;
403: the PD-FE (H) performs an authorization check for the request, including verifying whether the requested QoS resource is consistent with the policy rules of local operators and with user subscription information from an NACF; if the authorization check is passed, the PD-FE (H) makes an initial policy decision for the service request according to the user subscription information, the policy rules of the local operators, and the service information;
404: since the PD-FE (H) does not have the requested transport layer resource, the resource initialization request message is further sent to the PD-FE (denoted by PD-FE (V)) of the visited network;
405: the PD-FE (V) performs an authorization check for the request, including verifying whether the requested QoS resource is consistent with the policy rules of local operators;
406: the PD-FE (V) decides (viz. selects) the access network and the core network related to the requested QoS resource, and then the PD-FE (V), based on the above decision result, sends the resource initialization request message (availability check) to the TRC-FE (denoted by TRC-FE (V)) of the corresponding visited network to check the resource availability of the related network;
407: the PD-FE (V) makes a finial admission decision based on the result of the authorization check in Step 405 and the result of the resource availability check in Step 406; if the requested QoS resource is rejected, the PD-FE (V) sends a resource initialization response message to the PD-FE (H), and the message carries the reasons for rejection;
408: the PD-FE (V) sends the resource initialization request message to the PE-FE (denoted by PE-FE (V)) of the visited network so as to install a final decision policy; and
409: the PE-FE (V) installs the final decision policy from the PD-FE (V) and sends a resource initialization response to the PD-FE (V);
wherein Steps 408 and 409 are optional steps;
410: the PD-FE (V) sends the resource initialization response to the PD-FE (H); and
411: the PD-FE (H) sends the resource initialization response to the SCF.
In the related techniques, there is the above technical solution of resource and admission control for the application scenario as shown in FIG. 3, however, the technical solution is not applicable to the application scenario as shown in FIG. 2, viz. a technical solution of resource and admission control relating to inter-domain interaction and supporting roaming has not been found in the prior art for the scene of FIG. 2.